Pressureproof combustion chamber



Nov. 21, 1933. w. G. NOACK 1,935,659

PRES SUREPROOF COMBUSTION CHAMBER Filed Aug. 20, 1951 2 Sheets-Sheet 1II I 10 a fig. 2

26 26 a 1 Z 14 a V INVEHTOR 22 By W G. lYoack S M FMQQQ HTTOITNEY NOV.21, 1933. w NQAcK I PRESSUREPROOF COMBUSTION CHAMBER Filed Aug. 20, 19512 Sheets-Sheet 2 Patented Nov. 21, 1933 PATENT OFFICE PRESSUREPROOFCOMBUSTION CHAMBER Walter Gustav Noack,

Baden, Switzerland, as-

signor to Aktiengesellschalt Brown Boveri 8; Cie., Baden, Switzerland, ajoint-stock company of Switzerland Application August 20, and in Germany12 Claims.

This invention relates to pressure-proof combustion chamber forsubjecting combustible gases to combustion under high pressure, such asused in connection with gas turbines or steam generators, and it hasamong its objects simplified construction of such combustion chambersand reduction of their weight and costs.

The objects of the invention will be best understood from the followingdescription of exemplifications thereof, reference being had to theaccompanying drawings wherein Fig. 1 is a diagrammatic view of a steamgenerator with a combustion chamber made in accordance with theinvention;

Figs. 2 and 3 are horizontal and vertical sectional views, respectively,of a section of the combustion chamber of Fig. 1;

Figs. 4 and 5 are horizontal sectional views of combustion chambersembodying modifications o! the invention;

Fig. 6 is a vertical sectional view of the chamber section of Fig. 5;

Fig. 7 is a horizontal sectional view of a combustion chamberstructureembodying a modification of the invention;

Fig. 8 is a vertical sectional view of a chamber section embodying afurther form of the invention; and,

Fig. 9 is.a vertical sectional'view of a com-- bustion chamber structureembodying a modification of the invention. A

In my hopending application Serial No. 343,745, filed Marchl, 1929, Ihave disclosed a novel type of steam generator in which anextremely'high rate of steam generation is secured byperiodical- 1ysubjecting a combustible mixture to explosiontype combustion in apressure-proof chamber and utilizing the high pressure of the hotcombustion gases formed in the chamber for imparting to said gases avery high velocity through a set of gas tubestraversed on the outside bya. steam generating fluid, such as water, thereby securing a very highrate of heat transference from the hot gases to the water and, as aconsequence, very large steam generation within a relatively smallstructure.

The combustion chamber of such steam generator must be able to withstandthe high pressure of the combustion gases, and it must be able to do itwhile it is exposed to the high temperature of such gases. To meet thisdouble strain, of the pressure and of the heat, the walls of thecombustion chamber must be cooled, and this is ordinarliy done bypassing the steam generating fluid, such as-water, through coolingjackets sur- 1931, Serial No. 558,261,. September 1, 1930 rounding thechamber walls, the water taking up i the heat from the walls andconverting it into steam, which is applied for the production of power.The cooling medium is then subjected to the full steam pressure, whichmay be considerably higher than the pressure in the combustion chamber.The cooling jacket must thus be able to withstand a higher pressure thanthe interior of the combustion chambenand the diameter of the coolingjacket will be considerably greater than the diameter of the chamberwhich is itself of considerable dimensions. Both conditions entail theprovision of very thick walls for the combustion chamber and the coolingjacket, that is, heavy and costly bodies.

Since the heat must be led away through the walls of the chamber,it-must traverse the full wall thickness. There is accordingly a greattemperature gradient in the wall and large internal strains appear inthe wall material. Additional strains develop due to the large thermalexpansion of the hot chamber walls relatively to the surrounding cooljacket walls giving further serious design difllculties.

Similar conditionsexist also in gas turbines where the combustion gasesfor driving the turbine blades are generated at high pressure in apressure-proof combustion chamber and must be cooled to a lowertemperature that will not burn the blades before discharge into theturbine; The chamber is therefore likewise ordinarily cooled by a jacketcarrying water that takes up the heat and generates steam which issuitably utilized. The chamber as well as the jacket must both withstandhigh pressures, and their walls must be thick, giving, likewise, heavyand costly structures. e

In my prior application Serial ,No. 343,745, referred to above, I haveshown that a much superior water-cooled high pressure combustion chambermay be obtained, by eliminating the water jacket around the chamber,and, instead, mounting a set of water tubes on the inner'side of thepressureresisting walls of the combustion chamber and in this wayprotecting the wall of the chamber fromexcessive heating. Asthe tubesare of relatively small diameter, their wall thickness is small even forhigh pressures of the cooling liquid. Since the cooling tubes lie on theinner side of the wall, the wall is protected against radiation from thecombustion gases. The wall is only heated by the cooled gases collectingbetween the tubes and the wall, and by contact with the cooling tubes.The temperature of the walls cannot, therefore, be

' higher than the temperature on the rear side of the tubes. Thetemperature is accordingly low, and uniform within the wall, and thereis substantially no flow of heat through the walls. The excessivestresses the chamber walls due to the temperature differences betweenthe outer and inner-sides of the chamber walls and the jacket wall arethus eliminated. The only strain imposed on the chamber walls is that ofthe pressure of the gases in the chamber. The weight of the improvedwater-cooled pressure-proof combustion' chamber is thus considerablysmaller and their construction much simpler than in case of chambershaving an external jacket.

The present invention provides a further improvement in the constructionof pressure-proof combustion chambers with interior tubular wallcooling. In accordance with the present'invention the interior wall ofthe combustion chamber is itself formed by the tubes through which thehigh pressure cooling medium flows, the tubes being welded together toconstitute a smooth inner wall, and in some cases the welds between thetubes are made gas and pressure tight so as to hold the gas in theinterior of the chamber without additional outer walls.

In Fig. 1 the invention is shown as applied to the combustion chamber ofa steam generator of the type disclosed in my above referred toapplication Serial No. 343,745, Figs. 2 and 3 being detailed sectionalviews of the combustion chamber. The steam generator comprises apressureproof combustion chamber having a main cylindrical section 2with an inlet header 3 enclosing the bottom and an outlet header 4enclosing the top of the chamber. Within the walls of the inlet header 3is formed a water inlet chamber 5 and within the walls of the outletheader 4 is formed a water outlet chamber 6. A set of water tubes '1 ismounted along the periphery of the chamber 1 forming the inner wallsthereof, the tubes being surrounded by a cylindrical outer wall 8,having at its ends flanges 9 within which the ends of the water tubes 7are secured, as by welding. The tubes 7 are connected between the waterinlet chamber 5 and the water outlet chamber 6 to pass water that isheated and vaporized while passing through the tubes, the mixture of hotwater and admixed steam being discharged through a conduit 10 into asteam separator 11. The steam separates and collects in the upper partof the separator from where it is supplied to the load, and the water iscollected in the lower .part of the separator, fresh feed water beingsupplied thereto through pipe 12. The water from the separator 11 iscirculated through water tubes 7 by means of water pump 13 which isconnected by pipes 14 between the separator 11 and inlet 15 of waterchamber 5.

A combustible mixture, such as a gas or air with fuel' admixed thereto,is compressed by compressor 20 and periodically delivered to combustionchamber 1 through conduit- 21 and suitably operated inlet valve 22. Theadmitted compressed combustible charge is subjected to explosivecombustion in the chamber, for instance by ignition with spark plugsmounted on the interior wall of the chamber. The resulting high pressureis utilized to drive the hot combustion gases at a velocity of about 200meters per second or above through a set of gas pipes 26 connected tothe upper end of the chamber and leading through the interior of thewater tubes '7, the gases being discharged into the gas outlet duct, andtherefrom, through pipe 28 into a gas turbine where a part of the energystill remaining welded to the adjacent tube walls.

in the gases is applied to drive compressor 20 and thus serves toinitially compress the cornbustible charge supplied to the chamber.Additional driving power may be supplied to the compressor by anauxiliary motor 30, such as'a Diesel engine, coupled to the gas turbine29, the total power supplied by the motor and the turbine beingproportioned to be suflicient to produce in the compressor the pressurehead necessary for imparting to the combustion gases the high velocityand for driving the auxiliary gas turbine to supply a part or all of theinitial charging pressure. This charging and explosion process isperiodically repeated resulting in a continuous efficient generation ofsteam.

As pointed out before, the combustion chamber must be able to withstandthe high pressure developed by the explosive combustion of thecompressed charge while it is exposed to the high temperature of thegases. This is achieved in a way much superior to the prior practices.As seen in detail in Figs. 2 and 3, the main section of the combustionchamber is made by arranging the water tubes 7, which circulate thewater that is to be heated and converted into steam, axially parallelclose together to form the wall enclosing the interior of the chamber.The adjacent water tubes '7 are either directly welded to each other, orpreferably have the interior grooves between each other filled byinsertions 31 in the form of a round wire, or of a special form 32conforming to the outer surfaces of the adjacent tubes asshown in Fig.4, the insertions being The welding of the .tubes to each other formstight joints between the tubes and produces a tight enclosure. It isimportant to have the internal cylindrical surface of the chamber smoothand without interstices so as to prevent trapping of remnant burned orburning gases that might prematurely ignite the next fresh charge. Tothis end the interstices and junctions between the inner tube sides andinsertions are filled during the welding with filler material 33 and thewelds then ground with an emery wheel, so that the interior of thechamber Wall shall have the character of a continuous unitary wall.

In combustion chambers with water tubes arranged parallel to the chamberaxis as shown in Figs. 2 and. 3, the tubes are preferably surrounded bythe cylindrical wall 8, of steel or similar material. In suchconstructions, the water tubes 7, before being welded to each other attheir inner-sides, are'tacked, by welding, to the wall .8, at severalplaces, as indicated in Fig.

2 at"34, to insure their bearing against the wall.

The outercylinder wall 7 takes up the longitudinal strain exercised bythe bottom and top headers 3 and 4 on the main chamber section 2,andvalso' the tangential forces acting in the direction of thecircumference of the chamber section 2, although a part of thetangential pres sure may be taken up by the welding of the tubes. Sincethe water tubes 7 lie directly'on the inner side of the cylindrical wall8, the

temperature of the wall cannot be higher thanconstruction of acombustion chamber that is much lighter than ordinary high pressure,high temperature combustion chambers, eliminating also the complicatedconstruction problems arisingdue to the pressure and heat stresses inthe chamber walls.

Instead of cyindrical water tubes 7, tubes of special cross section maybe used for the chamber wall. Such arrangement is shown in Figs. 5 and6, where the distance between the tubes is increased, and their numberdecreased by pressing the water tubes 36 throughout their length to anoval shape. Each tube occupies a larger part of the chamber periphery,and the adjacent tubes are welded to each other and joined to form acontinuous smooth inner wall by welding and depositing a welding fillerat the junctions. The tubes retain their cylindrical shape only at theirends 37 inside the flanges 9, to facilitate their mounting. The watertubes for the chamber wall may also be of trapezoidal form 38, as shownin Fig. 7, to facilitate the building up of the cylindrical chamberwalls, the cross section of the tubes being well rounded or beveled atthe corners to provide junction spaces for receiving sufficientquantities of welding material.

Pressure-, and temperature-proof combustion chambers for steamgenerators and gas turbines in accordance with the present invention mayalso be made by helically woundtubes, as shown in Fig. 8. The individualturns 40 of the water tubes lie one above the other, forming acylindrical chamber, and the inner sides of the junctions of adjacenttubes are welded to each other and filled with welding inserts 41 andwelding metal 42 to provide a smooth interior surface like in theconstruction shown in Figs. 2 and 3. The end turns of the water. tubes40 are lightly welded to the flanges 44 to which the bottom and topheaders 3 and 4 are clamped. Water for absorbing the heat of the chambergases is circulated under pressure through tubes 40, the water beingadmitted and led away by suitable ducts 49 joined to the ends of thecoiled tubes. The tangential.

forces'in the circumference of the chamber pro-- duced by the internalpressure in the chamber are taken up by the tubes 40 themselves, and noexternal cylindrical wall is needed. The welding of the tube turnsprovides tight joints, and gives a tight pressure-proof chamber. Thelongitudinal stresses in the chamber wall, impressed by the bottom andtop headers 3 and 4 of the cham-- her, are taken up by tension bolts 45which also serve to bolt the bottom and top headers to the maincylindrical section formed by the tubes 40.

A lagging 47 is provided around the chamber which case, however, theremust be provided in addition to bolts 45 for taking up. longitudinalstresses, also several outer clamping rings surrounding the tubes andtaking up the tangential stresses produced by the internal pressure inthe chamber. v

,Instead of using cylindrical helically wound tubes for forming thecombustion chamber in Fig. 8, tubes of special profile, such as therectangular tubes shown in Fig. 9, may be employed, welded at thejunctions like the tubes of Fig. 7. 3

The present application is directed only to the features of my inventiondisclosed herein'involving a pressure resisting combustion chamber, thewalls of which are made of adjacently disposed tube elements heldtogether tight and pressure proof condition.- The steam generatorapparatus disclosed above in connection with the exemplification of theforegoing invention embodies many other novel features for causing hightemperature compressed combustion gases to discharge at a high velocityover a small evaporator structure and generate steam at a high rate asdescribed and claimed in my copending applications, Serial No. 333,453filed January 18, 1929, Serial No. 343,745 filed March 1, 1929, Serial"No. 343,746 filed March 1, 1929, Serial No. 375,138 filed July 1, 1929,Serial No. 414,428 filed December 16, 1929, Serial No. 419,026 filedJanuary 7, 1930, and Serial No. 558,260 filed August 20, 1931.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I'claim is 1. A pressure-resisting combustion chamber for steamgeneraors or gas turbines, comprising a chamber wall formed ofadjacently disposed metallic tube elements, closure members joined tosaid tube wall and constituting therewith a combustion chamber, meansfor admitting a comb ustible charge into said chamber and subjectingsaid charge to combustion under great internal pressure substantiallyhigher than the external pressure, and ducts connected to the oppositeends of said tube elements for passing therethrough a cooling fluidabsorbing heat from the hot combustion gases and maintaining within saidtube elements a pressure substantially higher than the externalpressure,'the tube elements forming said chamber wall being weldedv toeach other along their inner junction surfaces and being held togetherto maintain with said closure members said chamber in pressure-proofcondition.

2. A pressure-resisting combus ion chamber for steam generators or gasturbines, comprising a tubular chamber wall formed of adjacentlydisposed metallic tube elements, closure members joined to the oppositeends of said tubular chamber wall and constituting therewith acombustion chamber, means for admitting a combusiible charge into saidchamber and subjecting said charge to combustion under great internalpressure substantially higher than the external pressure, and ductsconnected to the opposite ends of said tube elements for passingthereihrough a cooling fluid absorbing heat from the hot combustiongases and maintaining within said tube elements a pressure substantiallyhigher than'the external pressure, the tube elements forming saidchamber wall being welded to' each other along their inner junctionsurfaces and being held together to maintain with said closure memberssaid chamber in pressure-proof condition.

3. A pressure-resisting combustion chamber 143 for steam generators orgas turbines, comprising a tubular chamber wall formed of adjacentlydisposed metallic tube elements, closure members joined to the oppositeends of said tubular chamber wall and constituting therewith acombustion chamber, means for admitting a combustible. charge into saidchamber and subjecting said charge to combustion under great internalpressure substantially higher than the external pressure, ductsconnected to the opposite ends of said 150 tube elements for passingtherethrough a cooling fluid absorbing heat from the hot combustiongases and maintaining within said tube elements a pressure substantiallyhigher than the external pressure, the tube elements forming saidchamber wall being welded to each other along their inner junctionsurfaces and being held together to maintain with said closure memberssaid chamber in pressure-proof condition, and additional means extendinglongitudinally along said tubular chamber wall to take up thelongitudinal wall stresses imposed by the pressure within said chamber.

4. A pressure-resisting combustion chamber for steam generators or gasturbines, comprising a tubular chamber wall formed of adjacentlydisposed metallic tube elements, closure members joined to the oppositeends of said tubular chamber wall and constituting therewith acombustion chamber, means for admitting a combustible charge into saidchamber and subjecting said charge to combustion under great internalpressure substantially higher than the external pressure, and ductsconnected to the opposite ends 'of said tube elements for passingtherethrough a cooling fluid absorbing heat from the hot combustiongases and maintaining within said tube elements a pressure substantiallyhigher than the external pressure, the tube elements forming saidchamber wallbeing welded to each other along their inner junctionsurfaces to form a smooth interior chamber surface and being heldtogether to maintain with said closure members said chamber in tight andpressure-proof condition.

5. A pressure-resisting combustion chamber for steam generators or gasturbines, comprising a tubular chamber wall formed of adjacentlydisposed metallic tube elements, closure members joined to the oppositeends of said tubular chamber wall and constituting therewith acombustion chamber, means for admitting a combustible charge into saidchamber and subjecting said charge to combustion under great internalpressure substantially higher than the external pressure, and ductsconnected to the opposite ends of said tube elements for passingtherethrough a cooling fluid absorbing heat from the hot combustiongases and maintaining within said tube elements a higher pressure thanthe pressure inside said chamber, the tube elements forming said chamberwall being welded to each other along their inner junction surfaces toform a smooth interior chamber surface and being held together tomaintain with said closure members said chamber in tight andpressure-proof condition.

6. A pressure-resisting combustion chamber for steam generators or gasturbines, comprising a tubular chamber wall formed or adjacentlydisposed metallic tube elements, closure members joined to the oppositeends of said tubular chamber wall and constituting therewith acombustion chamber, means for admitting a combustible charge into saidchamber and subjecting said charge to combustion under great internalpressure substantially higher than the external pressure, and ductsconnected to the opposite ends of said tube elements for passingtherethrougha cooling fluid absorbing heat from the hot jcombustiongases and maintaining within said tube elements a pressure substantiallyhigher than the external pressure, the tube elements forming saidchamber wall being welded to each other along their inner junctionsurfaces and having the grooves between said junction surfaces filledwith metal inserts weldedto said surfaces to form a smooth interiorchamber surface and being held together. to maintain with said closuremembers said chamber in tight and pressure-proof condition.

7. A pressure-resisting combustion chamber for steam generators or gasturbines, comprising a tubular chamber wall formed of adjacentlydisposed metallic tube elements, closure members joined to the oppositeends of said tubular chamber wall and constituting therewith acombustion chamber, means for admitting a combustible charge into saidchamber and subjecting said charge to combustion under great internalpressure substantially higher than the external pressure, and ductsconnected to the opposite ends of said tube elements for passingtherethrough a cooling fluid absorbing heat from the hot combustiongases and maintaining within said tube elements a pressure substantiallyhigher than the external pressure, the tube elements forming saidchamber wall having flat side walls welded to each other to form asmooth interior chamber surface and being held together to maintain withsaid closure members said chamber in tight and pressure-proof condition.c

8. A pressure-resisting combustion chamber for steam generators or gasturbines, comprising a tubular chamber wall formed of adjacentlydisposed metallic tube elements, closure members joined to the oppositeends of said tubular chamber wall and constituting therewith acombustion chamber, means for admitting a combustible charge into saidchamber and subjecting said charge to mbustion under great internalpressure substanti ly higher than the external pressure, ducts conn tedto the opposite ends of said tube elements for passing therethrough acooling fluid absorbing heat from the hot combustion gases andmaintaining within said tube elements a pressure substantially higherthan the external pressure, the tube elements forming said chamber wallbeing welded to each other along their inner junction surfaces and beingheld together to maintain with said closure members said chamber inpressure-proof condition, and tension bolts extending longitudinallyalong said tubular chambenwall to take up the longitudinal wall stressesimposed by the pressure within said ends of said tube elements forpassing therethrough a cooling fluid absorbing heat from the hotcombustion gases and maintaining within said tube elements a pressuresubstantially higher than the external pressure, the. tube elementsforming said chamber wall being welded to each other along their innerjunction surfaces and being held together to maintain with said closuremembers said chamber in pressure-proof condition, and a tubular wallextending between said closure member's around said tubular chamber wallin longitudinal direction to fake up the longitudinal and tangentialwall stresses imposed by the pressure within said chamber.

10. A pressure-resisting combustion chamber for steam generators or gasturbines, comprising a tubular chamber wall formed of metallic tubeelements helically wound adjacent to each other,

closure members joined to the opposite ends of said tubular chamber walland constituting therewith a combustion chamber, and means connected tothe ends of said tube elements for passing therethrough a cooling fluidabsorbing heat from the hot combustion gases and maintaining within saidtube elements a pressure substantially higher than the externalpressure, the tube elements forming said chamber wall being welded toeach other along their inner junction surfaces and being held togetherto maintain with said closure members said chamber in pressure-proofcondition. I

11. A pressure-resisting combustion chamber for steam generators or gasturbines, comprising a tubular chamber wall formed of metallic tubeelements helically wound adjacent to each other, closure members joinedto the opposite ends of said tubular chamber wall and constitutingtherewith a combustion chamber, means connected to the ends of said tubeelements for passing therethrough a cooling fluid absorbing heat fromthe hot combustion gases and maintaining within said tube elements apressure substantially higher than the external pressure, the tubeelements forming said chamber wall being welded to each other alongtheir inner junction surfaces to form a smooth interior chamber surfaceand being held together to maintain with said closure members saidchamber in tight and. pressureproof condition, and tension boltsextending longitudinally along said tubular chamber wall to take up thelongitudinal wall stresses imposed by the pressure within said chamber.

12. A pressure-resisting combustion chamber for steam generators or gasturbines, comprising a tubular chamber wall formed of adjacentlydisposed metallic tube elements, closure members joined to the oppositeends of said tubular chamber wall and constituting therewith acombustion chamber, means for admitting a combustible charge into saidchamber and subjecting said charge to combustion under great internalpressure substantially higher than the external pressure, ductsconnected to the opposite ends of said tube elements for passingtherethrough a cooling fluid absorbing heat from the hot combustiongases and maintaining within said tube elements a higher pressure thanthe pressure inside said chamber, and an additional tubular solid wallsurrounding said tubular chamber wall and joined to said closure membersto take up the chamber stresses and maintain with said closure memberssaid chamber in tight and pressure-proof condition.

WALTER GUSTAV NOACK.

